Have I done something wrong or does Mapnik not respect layers when rendering bridges over bridges?

See the south east corner of the Harrow Roundabout as it crosses (under) Westway on osm.org/?lat=51.520167&lon=-0.17988&zoom=18

There seems to be a general problem with mapping rural areas on Open Street Map, in the UK. It ranges from whole towns that almost aren't mapped to small hamlets, and their maze of connecting roads.

Towns I imagine we can gradually get to map - it's going to take a long time as it relies on local people doing it.

The small roads are a very time consuming thing to do, and can't be done feasibly on foot and even by bike would be seriously exhausting.

It's unfortunate that Yahoo seem to be the worst provider of online satellite imagery - the areas that we have the worst coverage directly correspond to those that aren't on the Yahoo imagery at good quality. Look at west Brighton for example, it cuts off exactly along the line of the imagery.

I've been looking at South West England - around Honiton, a town I know pretty well from many holidays near there over the years. I'd love to be able to map it, but there must be hundreds of miles of unmapped roads just within 10 miles of there... Have a look at Google Maps for example...

I'm sure I'm not the first to consider this. Does anyone have any ideas as to how sparsely populated areas are going to be mapped?

I've been mapping the Royal Holloway - University of London campus and I've had a couple of problems.

The main building is '8' shaped - a rectangular building with two large courtyards/quads. I'm not sure how to make it show like this, I've managed to cut out one of the quads but not the other. Anyone able to suggest how best to do this?

I've been busy mapping out the wooded areas of Windsor Great Park and correcting the paths and roads in the park, Englefield Green and Egham. Having patches of green over the park makes it look much better, though unfortunately the Yahoo! imagery runs out in the middle of the park - someone should suggest they buy some more. Anyone worried about what Microsoft might do to Yahoo! maps?

On an unrelated note, I noticed this annoying rendering issue:

Go to the linked map and go to zoom level 14 on Osmarender. You see a massive 'Truss's Island' label for what is a tiny place (< 150m long and about 30m wide). Mapnik does a better job of this and scales it more appropriately.

It seems to be caused by the 'place=island' value, Osmarender must assume that islands are significant I guess...

Back to work!

So, I've got a plant nursery to map - where does it go? I've put it as a farm, but a farm in (almost) central London seems somewhat odd...

osm.org/?lat=51.501295&lon=-0.204153&zoom=18&layers=B0FT

Ideas?